1. Field of the Invention
The present invention relates to a white light emitting diode, particularly to a chip-type white light emitting diode including a substrate layer and a packaging element, wherein the substrate layer and the packaging element are both made from a mixture including a curable resin, a curing agent, a phosphor material, and a modified thermal conductive nano-material.
2. Description of Related Art
In traditional light emitting diode device, the heat generated from the light emitting diode chip almost transfer to a heat-dissipating substrate by a heat-dissipating material, and then heat dissipate to surroundings by the heat-dissipating substrate. The heat is generated more quickly with an increased power of the light emitting diode chip, and be unable to heat dissipate through the heat conduction path timely and effectively. This makes light emitting diode chip damage and has a short lifetime. Therefore, how to heat dissipate for the light emitting diode chip effectively is an important issue.
TW patent publication No. 201304196 discloses a manufacturing method of a back-cutting light emitting diode (LED). Referring to FIG. 1 of No. 201304196, the manufacturing method of the back-cutting LED comprises the steps: (1) providing an array-type LED package structure 6 which includes a ceramic substrate 61, multiple light emitting units 62 disposed on a front-surface 611 of the ceramic substrate and coupled to the ceramic substrate 61, and a lens set 63 formed on the front-surface 611 of the ceramic substrate and covered the light emitting units 62, wherein the lens set 63 includes multiple lens 631 corresponding to the light emitting units 62 respectively; (2) disposing the array-type LED package structure 6 in a jig 7 which being filled with liquid resins 71, wherein the lens set 63 being toward and conduct the liquid resins 71, and the ceramic substrate 61 has a back-surface 612 of the ceramic substrate, which being exposed and corresponding to the ceramic substrate front-surface 611; (3) curing the liquid resins 71 to form a solid colloidal 72, this makes the array-type LED package structure 6 being fixed relative to the location of the jig 7 by the solid colloidal 72. Next, cutting the ceramic substrate 61 and lens set 63 of the array-type LED package structure 6 to form multiple back-cutting LED package structures 8 in a direction toward the solid colloidal 72 from the back-surface 612 of the ceramic substrate; (4) attaching a tape 9 to the back-surface 81 of each back-cutting LED package structure 8 simultaneously, and liquefying the solid colloidal 72 for returning to the liquid resins 73; (5) taking each back-cutting LED package structure 8 attaching on the tape 9 out of the jig 7, wherein some residues exist on the surface of each back-cutting LED package structure 8; (6) cleaning the residues on the back-cutting LED package structure 8; and lifting off each back-cutting LED package structure 8 from the tape 9.
In the said patent, the heat generated from the light emitting unit 62 just directs to surroundings by the ceramic substrate 61. Thus, the heat-dissipating efficiency is not good. Furthermore, due to the manufacturing method of the back-cutting LED needs to have a cutting process, the manufacturing method become more complicated and the ceramic substrate is brittle in the cutting process. If concerning with the thin demand, the ceramic substrate may be damaged easily in the cutting process so that the operating process has more limit, and the production rate would be influenced. Meanwhile, because the ceramic substrate 61 is opaque, this makes the back-cutting LED luminous with limitation.
TW patent publication No. 201210093 discloses a LED having a preferred heat-dissipating efficiency. Referring to FIG. 2 of No. 201210093, the LED includes a substrate unit 1, a silver conductive unit 2, a heat-dissipating unit 3, a light emitting unit 4, and a packaging unit 5. The substrate unit 1 includes a ceramic substrate 10. The silver conductive unit 2 includes two top conductive pads 21 disposed on the upper surface of the ceramic substrate 10, two bottom conductive pads 22 disposed on the lower surface of the ceramic substrate 10, and multiple penetrating conductive layers 23 penetrating the ceramic substrate 10 and coupling between each top conductive pad 21 and each bottom conductive pad 22. The heat-dissipating unit 3 includes a top heat-dissipating block 31 disposed on the upper surface of the ceramic substrate 10 and a bottom heat-dissipating block 32 disposed on the lower surface of the ceramic substrate 10. The light emitting unit 4 includes a light emitting element 40 disposed on top heat-dissipating block 31 and coupling between two top conductive pads 21 by two conductive wires W. The packaging unit 5 includes a package resin 50 disposed on the silver conductive unit 2 and the heat-dissipating unit 3 and covered the light emitting element 40. The package resin 50 can be made from a light-permitting resin 501 (e.g. silicone or epoxy) and phosphor powders 502.
In the said patent, the heat generated from the light emitting element 40 is conducted to surroundings by the top heat-dissipating block 31, the ceramic substrate 10, and the bottom heat-dissipating block 32, so that the heat-dissipating efficiency for the LED increases. Although the said patent can increases the heat-dissipating efficiency of prior LED package structure, but the LED thickness of the said patent is still too thick in the trend of thin LCD design. In addition, due to the design of the heat-dissipating element is complicated, the yield rate or production rate for the LED is not good. Furthermore, the method of manufacturing LED also has the cutting process similar to the said patent NO. 201304196. Therefore, the LED manufacturing process of No. 201210093 is complicated, and the ceramic substrate 10 is damaged easily. Meanwhile, due to the ceramic substrate 10 is opaque, this makes the LED luminous with limitation.
TW patent publication No. 200847476 discloses a light emitting diode package with two heat-dissipating paths. Referring to FIG. 3 of No. 200847476, the light emitting diode package includes a lens structure 101, a heat-dissipating material 105, a circuit board 107, a plastic cover 103, a LED chip 211, a ladder-type heat-dissipating clip 313, and a heat-dissipating substrate 315. The heat-dissipating material 105 includes a body portion 105a for carrying the LED chip 211 and an extending area 105b coupled with the body portion 105a. The LED chip 211 is coupled to the circuit board 107 by the conductive wire 121. The material of the heat-dissipating material 105 can be a metallic or ceramic material. The material of the lens structure 101 can be a polycarbonate or a silicon resin. The material of the heat-dissipating substrate 315 can be a metallic or non-metallic material. The heat-dissipating substrate 315 also can be a printed circuit board, a metal core printed circuit board, or a ceramic substrate. The material of the ladder-type heat-dissipating clip 313 can be a metallic or non-metallic material.
In the said patent, the heat generated from the LED chip 211 just directs to the heat-dissipating substrate 315 and surroundings by the body portion 105a and the extending area 105b of the heat-dissipating material 105 respectively. At the same time, the extending area 105b of the heat-dissipating material 105 and the heat-dissipating substrate 315 are buckled by the ladder-type heat-dissipating clip 313 to make the LED chip 211, the heat-dissipating material 105, and the heat-dissipating substrate 315 contact tightly, and further increase the heat-dissipating efficiency more. However, although the said patent can overcome the question of poor heat-dissipating efficiency in prior LED package structure, but the LED thickness of the said patent is still too thick in the trend of thin LCD design. In addition, due to the design of the heat-dissipating element is complicated, the production rate is not good. Meanwhile, due to the heat-dissipating material 105 is opaque, this makes the LED luminous with limitation.